1. Technical Field
The present invention relates to surgical devices such as implants or suture fastenings.
2. Description of the Prior Art
Mundell U.S. Pat. No. 4,506,681 shows the use of a prosthesis which includes a biodegradable thermoplastic material molded around electric resistance elements to allow for heating to soften to mold to a particular shape.
Polonsky U.S. Pat. No. 4,662,068 discloses cutting off most of the protruding ends of a plastic suture and heating them to secure the ends together.
Jacobs U.S. Pat. No. 4,750,492 shows crimping or clipping a biodegradable fastener or retainer on the end of a biodegradable suture.
The compound methyl methacrylate is an acrylic resin monomer which is sometimes used in surgery to fasten or grout implants of metal to bone, or hip or knee replacements to bone. It is usable only for bone to metal applications. Tissue reacts to it and in soft tissue it creates a fibrous scar. Further, it is not biodegradable.
The present invention includes an assembly for use in surgical applications in humans. The assembly may include two components, at least one of which comprises a heat bondable material. The first and second components are bond to each other by the application of heat to the heat bondable material, to make the heat bondable material soften, become tacky, and bond to the other component.
If only one of the components comprises a heat bondable material, the application of heat to the heat bondable material of that component causes the heat bondable material to soften and bond to the other component.
If both of the components comprise a heat bondable material, the application of heat to the heat bondable material of the components causes the heat bondable material of at least one and preferably each component to soften and bond to the other component.
The assembly can also include a first component, a second component, and a third component separate from the first and second components and comprising a heat bondable material. The application of heat to the heat bondable material of the third component causes the heat bondable material to soften and bond to the first and second components to interconnect the first and second components.
The heat bondable material is preferably a polymeric or composite material suitable for surgical applications and implantations in humans, and may be a biodegradable material where such is called for by the application.
The present invention may advantageously be embodied in heat bonded fastenings for sutures or K-wires, in which a variety of different suture anchors are usable, including expandable distal suture anchors. Such suture fastenings are easier to form and stronger than conventional tied knots. Other examples of assemblies embodying the present invention may include a metal bone plate which is held to bone by a metal bone screw and a nut of bondable material bonded to the plate to secure the connection; a wedge of bondable material bonded to a metal prosthesis to custom fit the prosthesis; and a surgical implant custom formed by bonding together a plurality of discrete elements one or more of which is bondable. Such embodiments are further described below.
The present invention may also provide a method of suturing body tissue. A portion of a suture is inserted into an opening in a retainer formed of a plastic material. At least a portion of the retainer is heated to a temperature in a transition temperature range of the plastic material forming the retainer. The suture is maintained at a temperature below the transition temperature range of a plastic material forming the suture while the retainer is heated. The plastic material of the retainer flows around the plastic material of the suture. A bonding of the plastic material of the retainer to the plastic material of the suture is effected by cooling the plastic material of the retainer to a temperature below its transition temperature range. The foregoing steps are performed without significant deformation of the plastic material of the suture.